Author + information
- Received August 13, 1985
- Revision received October 15, 1985
- Accepted October 18, 1985
- Published online March 1, 1986.
- Catherine M. Otto, MDa,1,
- Alan S. Pearlman, MD, FACC,
- Keith A. Comess, MD1,
- Robyn P. Reamer, RCPT,
- Carolyn L. Janko, RDMS and
- Lee L. Huntsman, PhD
- ↵aAddress for reprints: Catherine M. Otto, MD, Division of Cardiology, RO-22, University of Washington, Seattle, Washington 98195.
The severity of aortic stenosis was evaluated by Doppler echocardiography in 48 adults (mean age 67 years) undergoing cardiac catheterization. Maximal Doppler systolic gradient correlated with peak to peak pressure gradient (r = 0.79, y = 0.63x + 25.2 mm Hg) and mean Doppler gradient correlated with mean pressure gradient (r = 0.77, y = 0.51x + 10.0 mm Hg) by manometry. The transvalvular pressure gradient is flow dependent, however, and associated left ventricular dysfunction was common in our patients (33%). Thus, of the 32 patients with an aortic valve area less than or equal to 1.0 cm2at catheterization, 6 (19 %) had. a peak Doppler gradient less than 50 mm Hg.
To take into account the influence of volume flow, aortic valve area was calculated as stroke volume, measured simultaneously by thermodilution, divided by the Doppler systolic velocity integral in the aortic jet. Aortic valve areas calculated by this method were compared with results at catheterization in the total group (r = 0.71). Significant aortic insufficiency was present in 71 % of the population. In the subgroup without significant coexisting aortic insufficiency, closer agreement of valve area with catheterization was noted (n = 14, r = 0.91, y = 0.83x + 0.24 cm2).
Transaortic stroke volume can be determined noninvasively by Doppler echocardiographic measures in the left ventricular outflow tract, just proximal to the stenotic valve. Aortic valve area can then be calculated as left ventricular outflow tract cross-sectional area times the systolic velocity integral of outflow tract flow, divided by the systolic velocity integral in the aortic jet. Using this approach, noninvasive aortic valve areas compared well with valve areas calculated at catheterization (r = 0.86, y = 0.96x + 0.19 cm2). A simple index, derived as the ratio of the systolic velocity integral in the left ventricular outflow tract to that in the aortic jet, provided better identification of patients with severe stenosis (sensitivity = 97%) than did the Doppler pressure gradient alone (sensitivity = 81%).
These results show that noninvasive calculation of aortic valve area using Doppler echocardiography is feasible. The simple Doppler ratio may be useful clinically for identifying patients with severe stenosis, especially when low transaortic flow is suspected.
- Received August 13, 1985.
- Revision received October 15, 1985.
- Accepted October 18, 1985.
- American College of Cardiology Foundation